Comparison of the in vivo efficiency of photofrin II-, mTHPC-, mTHPC-PEG- and mTHPCnPEG-mediated PDT in a human xenografted head and neck carcinoma
✍ Scribed by Tobias Reuther; Alexander C. Kübler; Uwe Zillmann; Christa Flechtenmacher; Hannsjörg Sinn
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 200 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0196-8092
- DOI
- 10.1002/lsm.1123
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✦ Synopsis
Abstract
Background and Objective
One of the approaches to enhance the selectivity and efficiency of photodynamic therapy (PDT) was the conjugation of the photosensitizer meta‐tetrahydroxyphenylchlorin (mTHPC) to the water‐soluble polymer polyethylene glycol (PEG). Several studies have demonstrated that mTHPC‐PEG has a higher selectivity and a longer circulating half‐life than free mTHPC, whereas no in vivo effect of this benefit could be seen.
Study Design/Materials and Methods
In a model of RAG‐2‐mice bearing a human oral squamous cell carcinoma xenograft (XF 354), the in vivo efficiency assessed as growth retardation or remission caused by Photofrin II and free mTHPC was compared with mTHPC coupled in two different ways to polyethylene glycol (PEG). One hundred and fourty‐nine female RAG‐2‐mice were randomised into one control group and 13 therapy groups. Treatment parameters were adapted from those routinely applied in animal studies.
Results
Photofrin II‐mediated PDT and mTHPC‐mediated PDT were both in vivo highly effective, whereas mTHPC induced less scars. The in vivo results after mTHPC‐PEG‐mediated PDT were disappointing, whereas the effectiveness of mTHPCnPEG‐mediated PDT, a newly coupled macromolecular photosensitizer, were promising.
Conclusions
These results demonstrated the impact of the method of linkage between the photoactive agent mTHPC and polyethylene glycol (PEG) upon the in vivo effectiveness. mTHPC and mTHPCnPEG are promising photosensitizers for the future, especially for the cosmetic treatment needs of head and neck surgery. Lasers Surg. Med. 29:314–322, 2001. © 2001 Wiley‐Liss, Inc.